Dredge pot roast in flour. In a Dutch oven, heat oil until sizzling. Brown pot roast on all sides in oil. Remove roast from pot, add onions and cook until translucent. Put roast back in pot. Add water, garlic and all other ingredients. Stir well. Bring to boil. Cover and reduce heat. Simmer for at least four hours, until meat is fork tender. Remove from heat and cool until you are able to comfortably handle meat. Place meat on cutting board and using two forks, shred the beef. Return meat to pan and mix in spices.Any unused meat can be frozen for future use.